With Wonder as musical advisor, Kurzweil and his colleagues developed the Kurzweil 250 (K250) and introduced it to the public in 1984. The Kurzweil 250 is considered the first electronic musical instrument to accurately emulate the complexities of acoustic instruments.

In 1990, Kurzweil Music Systems was sold to Young Chang, the first Korean manufacturer of musical instruments and one of the leading manufacturers of acoustic pianos in the world. Although the K250 was discontinuted in 1990, the Kurzweil Music Systems division of Young Chang continues to produce industry-leading products, including the K2000samplingsynthesizer series and the top-of-the-line K2600 series.